1. Field of the Invention
The present invention relates to a monolithic refractory material used in refractories and refractory ceramic products, and more particularly to a monolithic refractory material having low expansibility, high strength, and crack extension resistance used for the purpose of repairing, protecting, modifying, filling, and forming the surface, adhesive surface, interface, or joint of low-expansion fire bricks and refractory ceramic products.
2. Description of the Prior Art
Hitherto, a monolithic refractory material is used as an adhesive for refractories. Such monolithic refractory material is usually prepared by selecting an inorganic aggregate and a fine powder according to the purpose, and kneading in water, as disclosed in patent document 1 or patent document 2. However, since water is used as solvent, a sufficient strength may not be obtained, and though an aggregate of high melting point is used in order to improve the refractory property and corrosion resistance, a far-flung particle size distribution is obtained with the average particle size at the center, and as crack extension is great, strength is insufficient. Hence at the present there is no monolithic refractory material satisfying all of low expansibility, high strength, and crack extension resistance.
On the other hand, it has been also proposed to use the monolithic refractory material as repairing material, protective material, modifying material, or filler for repairing, protecting, modifying, and filling the surface of low-expansion ceramic product. Such mortar contains silicon carbide to adjust the thermal expansion, and maintains a low expansibility. However, since silicon carbide is non-oxide, and involves a problem of oxidation, and low expansibility cannot be maintained permanently, and the bond strength is lowered due to deterioration by oxidation. Further, since water is used as solvent, the adhesion strength is lowered. Accordingly, an oxide additive is used for improving the strength, but the thermal expansion is increased in this case.
Or, as shown in patent document 1, by mixing an aggregate of particle size of 2 mm or more and Portland cement, a mortar of superhigh toughness is proposed, but although the high strength is achieved, low expansibility and crack extension resistance cannot be improved.
As shown in patent document 3, a mixture of cordierite powder and water is proposed as coating material for modifying the surface of ceramic product, but although the low expansibility and high strength are achieved, crack extension resistance cannot be improved.    [Patent document 1] Japanese Patent Application Laid-Open (JP-A) No. 2005-67945    [Patent document 2] JP-A No. 1991-75275    [Patent document 3] JP-A No. 2004-231506